PSI - Issue 81

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ScienceDirect

Procedia Structural Integrity 81 (2026) 73–77

© 2026 The Authors. Copy from the contract: Published by ELSEVIER B.V. This is an open access article under the CC BY-NC-ND license (https://creativecommons.org/licenses/by-nc-nd/4.0) Peer-review under responsibility of DMDP 2025 organizers Keywords: timber, beam, load, bending, stress-strain state, bearing capacity, temperature and humidity regime, long-term service. 1. Introduction Timber is often used in structures for decades and even centuries (Sekino and Korai (2018); Aleksiievets et al. (2024); Bader and Nemeth (2018); Homon et al. (2024); Luo et al. (2023); Zhao et al. (2020)). The physical and mechanical properties of timber depend on service conditions (Moya and Bano (2017); Homon et al. (2025); Thelanderson and Larsenn (2003); Green and Kretschmann (1992); Roos et al. (2010); Gong et al. (2019)). These properties are influenced by the temperature-humidity regime and the type of loading. During long-term service, certain changes may occur in the timber structure (Roshchuk et al. (2024); Wang et al. (2020); Diza Lestari et al. (2018); Matviiuk et al. (2025); Gerhards (1982); Köhler et al. (2007)). Load -bearing timber elements and structures may be in service for long periods as roof truss systems and load-bearing beams (Ivaniuk et al. (2025); Shams Huq et al. (2025); Pavluk et al. (2025); Betts et al. (2010); Sobczak-Piastka et al. (2010); Lamichhane et al. (2025)), as well as arches, floor trusses, columns, bridges, walkways, and other structures. They may be made of solid or glued laminated timber (Andor and Bellovics (2020); Mykhailovskyi and Komar (2024); Anshari et al. (2017)). The temperature-humidity regime, type of loading, and service life of timber elements and structures significantly affect their structural design and assessment (Gomon et al. (2023); Abstract The results of experimental studies on rectangular-section timber beams subjected to short-term loading after long-term service are presented. The experiments were carried out on bending elements under various temperature and humidity conditions and with different levels of damage. The average bearing capacity of the rectangular-section beams was determined. It was established that the bearing capacity of beams operated under normal service conditions did not significantly decrease. However, for bending elements exposed to deteriorated temperature and humidity conditions, a significant reduction in bearing capacity was observed. The failure modes of the experimental beams are presented and discussed. VIII International Conference “In - service Damage of Materials: Diagnostics and Prediction“ (DMDP 2025) Structural performance of timber beams after long-term service: an experimental study Victor Datsiuk a , Sviatoslav Homon b, *, Oleksandr Lukianenko b , Svyatoslav Gomon b , Yurii Puhach b , Petro Gomon b , Nadiia Kis c , Iryna Kutsyna c a Lutsk National Technical University, Lvivska 75, 43018 Lutsk, Ukraine b National University of Water and Environmental Engineering, Soborna 11, 33000 Rivne, Ukraine c Uzhhorod National University, 14 University Str., 88000 Uzhgorod, Ukraine

* Corresponding author. Tel.: +38-096-202-09-07; fax: +0-000-000-0000 . E-mail address: homonsviatoslav@ukr.net

2452-3216 © 2026 The Authors. Copy from the contract: Published by ELSEVIER B.V. This is an open access article under the CC BY-NC-ND license (https://creativecommons.org/licenses/by-nc-nd/4.0) Peer-review under responsibility of DMDP 2025 organizers 10.1016/j.prostr.2026.03.013